Apparatus storing cold liquids and method of making such apparatus



Sept- 25, 1962 w. L. MORRISON 3,055,532

APPARATUS sToRING com LIQUIDS AND METHOD oF MAKING SUCH APPARATUS Filed July 6, 1953 4 Sheets-Sheet 1 i I A Sept. 25, 1962 w. MoRRlsoN 3,055,532

APPARATUS STORTNG com LIQUTDS AND METHOD oF MAKING SUCH APPARATUS Filed July 6, 1955 4 Sheets-Sheet 2 Sept. 25, 1962 w. L. MORRISON 3,055,532

APPARATUS STORING CCLD LIQUIDS AND METHOD OF MAKING SUCH APPARATUS Filed July 6, 1953 4 Sheets-Sheet 3 M Q. w 7/ MJ Sept. 25, 1962 w. L. MORRISON APPARATUS sToRING com LIQUIDs AND METHOD oF MAKING sucH'APPARATus 4 Sheets-Sheet 4 Filed July 6, 1953 Patented Sept. 25, 1962 3,055,532 APPARATUS STORNG CLD LIQUIDS AND METHOD F MAKING SUCH APPARATUS Willard L. Morrison, Lake Forest, Ill., assigner, by mesne assignments, to Couch International Methane Limited,

Nassau, Bahamas, a corporation of the Bahamas Filed July 6, 1953, Ser. No. 366,125 7 Claims. (Cl. 220-22) My invention relates to improvements in tanks for storing cold liquefied hydrocarbons such as methane at atmospheric pressure and to the method of lining and insulating such tanks. The invention has to do with the manufacture of and use of an insulating container of the type disclosed in my co-pending application Serial No. 288,214, Afiled May 16, 1952, for insulating Container and Method of Storing Cold Liquefied Volatile Hydrocarbons and the Like, now abandoned.

Since the insulating lining for the tank or vessel for storage of such superchilled exceedingly cold liquid hydrocarbons as methane and the like at temperatures in the order of 258 F. is provided with an interior insulating lining which protects the liquid against excessive heat flow and at the same time protects the metallic supporting jacket or drum against such heat loss as might interfere with the structural strength of the metal, it is of the utmost importance that the lining be continuous, `without leaks or voids which might permit the escape of the cold liquid into contact with the metal.

If the lining is made of staves of balsa wood or the like, that lining must be installed in the tank or shell at ordinary ambient Working temperatures in the order of say 70 F. Then when cold liquid methane is inserted in the tank, the staves will shrink and it would -be very dangerous and very undesirable if such shrinkage should permit escape of the liquid through the cracks or voids left between adjacent staves, as this would bring the liquid into contact with the steel drum enclosing the insulating staves with damaging effect.

This shrinkage may be compensated for if the staves forming the insulating lining in the drum are precompressed. Under these circumstances when they shrink under the cold of the liquid methane, they will not separate.

When the staves of a wooden barrel are assembled, it is easy enough to press them by exerting a tension on the -barrel hoops but when the staves must be assembled in a container or tank, many feet in `diameter and of the great strength needed to support the load of many tons of the liquid, this method cannot be used.

I propose therefore first to assemble the tank or drum, riveting or Welding the steel together in the usual way. The staves forming the lining will be then assembled inside the drum. The staves, however, will be dried to a ,moisture content far below the moisture content they would have when exposed to the atmosphere and this will shrink them substantially. The mating surfaces of the staves will be coated with a suitable adhesive and assembled to line the tank top, bottom and sides. The atmosphere in the tank will be maintained at a sufficiently low moisture content during the assembly so that the staves, until assembly is completed, will remain in the dry, shrunk condition. As assembly continues the adhesive will be dielectrically heated to cement the staves together and cement the outer layer of staves into and against the steel tank wall, though under some circumstances, it will be sufiicient to allow the expansion of the staves resulting from moisture increase to exert a sufficient holding pressure upon the tank.

After the lining has been installed, it is desirable in view of the necessity for uniform conditions to positively and rapidly increase the moisture content of the staves in Y order that uniform compression may prevail. This may be accomplished by injecting steam or moist air into the tank'or drum. On the other hand, if the assembly can be allowed to stand long enough with the interior of the insulated tank exposed to the ambient atmosphere, the lining will without further steps gradually resume the normal moisture content and so the pre-loading resulting from this expansion will build up gradually, but if this is done, time must be given to insure such pre-loading or such expansion before the cold liquid hydrocarbon is put into the tank.

When balsa wood is first produced in its natural habitat, it can be naturally dried to somewhere in the neighborhood of twenty percent moisture. In New Orleans, for example, the natural humidity of the balsa wood would be in the order of l2 percent; in Chicago, in the order of 8 percent. I propose that the wood will be dried down to three to live percent moisture before assembling in the tank. When it is allowed to or forced to absorb moisture up to eight or twelve percent, it will expand in the order of one percent and when it is cooled by the cold liquid gas down to temperatures in the order of 258 F. it will shrink as a result of cooling from one-half to th-ree-quarters percent. Thus even at minimum temperatures there will remain some pre-compressing or pre-stressing of the lining.

Preferably, since balsa wood of commerce comes in fairly small sizes, I propose'to build up individual staves made of a plurality of pieces of the balsa wood cemented or glued together though under some circumstances, they might be held together by compression. Each stave will preferably be three or four inches thick and its width will be the width of the desired body of insulation. The lining will thus be built up with the thermosetting glue between adjacent staves so when an electrode is presented on the inside and the wall of the tank serves as an electrode on the outside, the glue layer will be perpendicular to the electrodes which is the desired arrangement.

The glue or cement holding the outside of each stave against the tank wall can not be heated dielectrically so after assembly is complete, this glue can be heated by a torch or other means heating the outside ofthe tank. The metal wall being a good heat conductor, this will result in causing the thermosetting glue on the outside to set and harden to hold the lining in the tank.

The oor of the tank will be built up just as are the staves and this floor will be laid dimensionally at least somewhat roughly, so long as at least the lower part of each board comes out generally to the Wall of the tank. After the floor is laid, the ends or sides, as the case may be, of the staves or boards making up the floor will be accurately sanded or cut at an angle of approximately 45 so `as to provide around the outer periphery of the structure a channel of uniform width and uniform dimension. The staves will be pre-sanded or pre-cut to approximately the same angle but in View of possible Variations in stave dimensions or tank dimensions or both, the lower ends of the staves will be sanded in place. This can be done by using the accurately sanded 45 angle floor surface as a template, the sanding belt being supported by the oor surface with the sand side contacting the roughly finished end of each stave. The stave will then be seated usually without any glue between the stave and the oor so that there will be a communication of the pores of the wood in the floor with those in the staves.

A somewhat similar method will be applied with respect to the upper ends of the staves. They will be sanded with reasonable accuracy and thenthe roof or ceiling 70 boards will be installed and sanded to conform to the upper ends of the staves. Again if glue is not used, there will be a free communication of the pores.

This pore alignment situation prevails with respect to the build up of each stave. Each stave will include a plurality of pieces shorter than the length of the stave and narrower than the total width of the stave. The mating ends of pieces built in the stave may be pressed together without glue, the stave elements being held together by the glue between their sides so that the possible ow of gas along the pores will not be interfered with.

If desired, however, all these surfaces may be glued in which case, gas movement along the pores from one piece to another will, of course, be prevented.

My invention is illustrated more or less diagrammatically in the accompanying drawings wherein:

FIGURE l is a horizontal section through a vessel and tank embodying my invention.

FIGURE 2 is a vertical section on an enlarged scale along the line 2 2 of FIGURE l.

FIGURE 3 is a section on an enlarged scale along the line 3 3 of FIGURE l.

FIGURE 4 is a side elevation of one of the assembled staves or planks used to form the tank lining.

FIGURE 5 is a section on an enlarged scale along the line 5-5 of FIGURE 4.

FIGURE 6 is a section on an enlarged scale along the line 6-6 of FIGURE 2.

FIGURE 7 is a section along the line 7-7 of FIG- URE 6.

Like parts are indicated by like characters in all the drawings.

1 indicates the hull of a vessel or barge adapted to contain one or more tanks. 2 is a tank mounted in the hull. The ldetails of the support of the tank in the barge form no part of the present invention and are not illustrated except for the studs 3 which indicate the fact that the tank is built into the barge in fixed position therein.

The tank is cylindrical, about a vertical axis and includes metal cylindrical side wall 4, bottom wall 5 and top wall 6 which latter may well form part of the deck of the barge. The tank is lined top, bottom and sides by a plurality of -assembled balsa wood staves or beams as illustrated in specific detail in FIGURES 4 and 5. Each beam or stave is made up of a plurality of short balsa or similar wood pieces cemented together in overlapping relationship so as to form a one piece stave extending from top to bottom of the tank in which case it is tapered as indicated in FIGURE 5, the inner width of the stave being narrower than the outer width and being formed along radial lines to conform to the circular contour of the tank, or for top or bottom of the tanks formed in the shape of a beam, parallel sided. The mating ends of beams and staves are cut on a diagonal as indicated in FIGURE 3.

As noted in detail in FIGURE 6 these staves are arranged side by side to form a continuous barrel like vertical insulating lining, and on their opposed faces are grooved as at 7, the mating grooves `forming channels or passages extending throughout the body of the insulating lining. As illustrated especially in FIGURE 3 the channels or conduits in beams and staves intersect so that there is a possibility of free gas or liquid movement along these channels' or ducts throughout the entire body of the insulation.

'Ihe beams and staves are as above noted of balsa wood, a wood which, while exceedingly light and furnishing excellent insulation, is rather easily mutilated. Therefore in order to protect the lining, it is shielded by a relatively thin sheet of, for example, Sitka spruce as indicated at 8, the spruce boards being lapped or butted together. Sitka spruce is strong enough to support the impact of any solid material that may enter the tank and to permit workmen to walk around on it without danger of damage and it is, of course, porous so that gases and liquid may pass through it and enter the balsa wood lining.

In order that the iloor and roof beams and staves may i lit snugly and accurately into the tank they are cut away at their outermost corners as indicated at 9 so that they will not have sharp terminal edges which might interfere with proper assembly in the tank because of slight irregularities in the joining of the vertical and horizontal tank walls.

The tank which is much larger in diameter than in height will in many instances be 50 feet or more in diameter and since it is intended to contain very large quantities of liqueiied hydrocarbon such as methane and the like for navigation both on inland and ocean waterways it is important to prevent or limit surging of the liquid contents of the tank which might, if not controlled, build up dangerous impact pressures. Moreover, it is important to support the roof of the tank mechanically because the tank is intended to contain vaporized liquids at substantially atmospheric pressure. The means for providing this support and preventing excessive agitation of the fluid will now be described.

1@ is a cylindrical column or standpipe located at the center of the tank. The floor lining 8 carries a pedestal 11 into which the standpipe 10 may t so as to center the lower end of the standpipe in the tank. The upper end of the standpipe carries angle struts 12 which engage and support the ceiling lining 8 and the standpipe carries at its upper end and slightly larger in diameter than the standpipe, a collar 13. The roof beams terminate short of the collar 13.

Extending vertically between the lining 8 of the roof and ceiling are vertical posts or studs 14 and supporting walls 15 arranged throughout the tank so as to divide it up into a plurality of chambers. Manholes 16 in the column and 17 in the walls 15 permit access to the chambers in the tank. There are apertures as indicated for example at 18, 19 and the like, through or around the partitioned walls so that as liquid is fed to or withdrawn from the tank the level in each chamber remains constant, there being no hydrostatic head applied to the walls 15, the walls being present merely to prevent excessive lateral liquid movement.

Since these tanks are designed for the storage and transportation of liquid hydrocarbons such as methane which boil at atmospheric pressure at temperatures in the order of -258 F. the insulating walls while exceedingly important will never be adequate to completely prevent entrance of heat to the liquid mass, so there will also be some measure of evaporation. The evaporated gas must be permitted to escape from the tank in order that the pressure in the tank may remain at all times substantially at atmospheric. There will also be some measure of penetration of the liquid through the interior sheathing into the balsa insulating lining. How far that penetration may extend is of small moment so long as the cold liquid itself is not allowed to contact the steel walls of the tank and bring them down to the excessively low temperatures of the liquid which might have deleterious effect on the tank and barge.

Provided the thickness of the insulating lining is suflicient it will also occur that as the liquid migrates outwardly in capillary filaments through the insulating wood it will be met by heat entering the tank from the outside which heat will vaporize the ends of the capillary filaments so that gas will be formed in and to some extent circulate through the body of the insulating lining. Such gas will lind its way into ducts 20, 21 formed by the grooves 7. These ducts are arranged in two series of connected passages, 20 adjacent the inside of the lining, 21 adjacent the wall of the tank. The series of ducts 20 discharge inwardly through the ceiling lining past ball check valve 22 so that gas evolved in the inner portion of the insulating lining may freely reach the top of the tank above the liquid level. The purpose of the check valve 22 is to prevent swashing of liquid into the duct series 20 while permitting free escape of gas therefrom.

The outer series of ducts 21 discharge inwardly radially into the channel 23 between the collar 13 and the roof beams and thence discharge through a port 24 into the standpipe 10. Ports 25 adjacent the upper end of the standpipe permit gas from the upper portion of the tank also to enter the standpipe. The means for handling and controll-ing the gas after it reaches the standpipe form no partof the present invention and are therefore not illustrated.

The use and operation of my invention are as follows:

The steel portion of the tank and the barge will be assembled and erected in the usual manner for steel structures. The insulating lining will be formed of built up beams and staves. The reason for this is that balsa wood, the preferred Wood, is found in commerce in small pieces and while it might be possible to build up the lin ing in small pieces as brick paving is laid, this would result in inaccuracies and Weaknesses which might be exceedingly undesirable. Therefore the beams are assembled outside the tank, cut to desired length and laid to form a lloor, the floor being preferably cemented to the wall of the tank and the adjacent beam or oor members being glued together at their opposed faces to produce a self-sustaining structure. The ends of the beams around the periphery of the tank are chamfered as are indicated in FIGURE 3 and preferably after they are assembled Will be cut or linished to true conical contour. Thereafter the Sitka wood floor will be laid upon the balsa floor beams so that men may walk on and work in the tank without danger of damaging the insulation. The vertical staves shaped to conform to the tank and to the floor beams will be assembled to line the cylindrical tank wall. Since the ends of the beams will have been previously cut or shaped to a true cone, each stave can well lit in place, the ends of the staves being easily shaped to a cone before assembly. The staves will be cemented to the Wall of the tank and to one another to complete the cylindrical portion of the lining.

The next step is to finish the upper ends of the staves forming the cylindrical lining to a true cone which cornpensates for any slight irregularities that may have resulted in shaping and assembling the staves. The Sitka spruce lining will also be applied and then the ceiling beams, each one cut on the outside to a cone to t the upper conical boundaries of the staves, will be applied and any inaccuracies can be taken care of on the outer boundaries of the channel 23 about the standipe. Then the spruce lining for the ceiling is placed on the roof of the tank and the ceiling lining being supported by temporary structure until the vertical supporting beams and partition Walls are inserted between the oor and ceiling.

By this arrangement the entire oor, roof and side walls of the steel tank will be completely masked from contact with the cold liquid contained in the tank. The only place where metal cornes in contact with the liquid is at the standpipe and the standpipe is insulated from the metal wall of the tank by the insulating collar 26. The standpipe itself must be of metal because of mechanical reasons for handling and treatment of the liquid and vaporized gas.

I claim:

1. In combination a metal tank, an insulating lining therefor of relatively soft porous wood covering the metal surface and continuous to protect the metal from contact with the liquid contents of the tank, an inner protective layer of harder, more Wear resistant porous wood carried by and masking the soft wood liner, a plurality of vertically disposed apertured partitions dividing the tank into a plurality of irregularly shaped connected chambers, said partitions being supported by the inner protective layer.

2. A storage tank for liquefied cold hydrocarbons and the like comprising metal, generally horizontal, top and bottom and vertical cylindrical Walls, an insulating lining of self-supporting porous material covering the metal walls, a metal standpipe within the tank supporting the top wall and insulated by the lining from contact with the metal tank walls.

3. A storage tank for liquefied cold hydrocarbons and the like comprising metal, generally horizontal, top and bottom and vertical cylindrical walls, an insulating lining of relatively soft porous self-supporting material covering the metal walls, an inner protective layer of harder, more resistant porous insulating material such as Sitka spruce carried by and masking the softer lining, a metal standpipe within the tank supported at its lower end on the protective layer extending upwardly to project above the metal top wall insulated therefrom by the lining and providing means in contact with the lining for the support of the top Wall.

4. In combination a metal tank, an insulating lining therefor of relatively soft, porous wood such as balsa covering the metal surface and continuous to protect the metal from contact with the liquid contents of the tank, there being a plurality of connected channels within the insulating lining open adjacent the top of the tank, means associated with the open end of the channel system to permit movement of fluid from the channel directly to the tank and adapted to prevent entrance of liquid from the tank into the channel.

5. In combination a metal tank, an insulating lining lining therefor of relatively soft, porous wood such as balsa covering the metal surface and continuous to protect the metal from liquid contents of the tank, there being two parallel systems of channels within the lining, one system adjacent the inner surface of the lining, the other system adjacent the outer surface of the lining, each system being open adjacent the top of the tank for discharge of fluid therefrom.

6. In a metal tank, a relatively thick, pre-compressed layer of soft, porous material pervious to liquefied hydrocarbon and gas, held under pressure in the tank to define a continuous uninterrupted insulating lining completely masking the metal Walls thereof, a relatively thin uncompressed layer of harder, tougher, porous and pervious material carried by and masking the pre-compressed insulating lining, a plurality of Walls contained between the top and bottom of the tank supported by the uncompressed layer of harder material, dividing the tank up into a plurality of relatively small irregular communicating charnbers.

7. A tank for storage of cold liquid hydrocarbons and the like comprising metallic vertical and horizontal Walls joined to define a closed metallic tank structure, a porous lining for the tank of relatively soft wood and the like completely masking the entire top, bottom and side areas of the metallic tank wall, a relatively thin wear resistant porous inner wood lining supported by the insulating lining, a plurality of vertical partition walls in contact with the inner lining dividing the interior of the tank into an irregular series of chambers, the walls -being apertured to permit automatic equalization of the liquid in the chambers but adapted to prevent excessive splashing movement of the liquid.

References Cited in the file of this patent UNITED STATES PATENTS 135,232 Manning Jan. 28, 1873 338,948 Gillette Mar. 30, 1886 472,119 Hermann Apr. 5, 1892 595,955 Loughin et al Dec. 2l, 1897 886,075 Remington Apr. 28, 1908 1,974,465 Lewis Sept. 25, 1934 2,121,675 White June 21, 1938 2,470,986 I ackson May 2A, 1949 2,676,773 Sanz et al. Apr. 27, 19,54 

